Refrigerating apparatus



G. R. OHMART REFRIGERATING APPARATUS July 7, 1936.

Filed. Oct. '7, 1932 2 Sheets-Sheet 1.

INVENTOR. Gkavqmv 1P. w/mmer ATTORNEY.

- July 7, 1936.

G. R. OHMAR-T REFRIGERATING APPARATUS Filed Oct. 7, 1932 2 Sheets-Sheet2 INVENTOR. 1 GRRY67'0/1 P. Unmmer ATTORNEY.

Patented July 7, 1936 REFRIGERATIN G APPARATUS Grayston R. Ohmart,Detroit, Mich assignor to Kelvinator Corporation, Detroit, Mich, acorporation of Michigan Application October 7, 1932, Serial No. 636,631

14 Claims. (01. 74-66) This invention relates to refrigeratingapparatus, and more particularly to refrigerating apparatus of thecompression type.

It is oneof the objects of this invention to provide a refrigeratingsystem of the type including a compressor, a driving motor, a condenserand a refrigerant evaporator and an im-,

proved arrangement for cooling the condenser which is especiallyapplicable to refrigerating apparatus wherein the motor and thecompressor are both entirely enclosed in a fluid-tight. or hermeticallysealed casing.

Another object is to provide a'fan which is cated exteriorly of thecasing for cooling the condenser and to arrange for transmitting powerfrom the motor within the casing to the fan by an improved mechanicalconnection without, in'

any way, affecting the fluid-tight qualities for hermetically sealingthe casing enclosing the motor and the compressor.

Another object of this invention is to provide an improved powertransmitting joint for transmitting power from the interior to theexterior of a hermetically sealed casing with but a neg-' ligible amountof friction and without in any way affecting the hermetical sealingqualities of the casing.

Another object of my invention is to provide intake and dischargechambers for the compressed fluid, which are of sufiicient size so as toeven out the periodic suction'and discharge to and from the cylinder soas to provide silencers which enable the operation of the compressorwithout pulsation hums.

an improved unloader which is arranged to bypass refrigerant from thecompression cylinder until the motor'attains a certain speed and whichis also arranged to prevent the by-passi'ng of 40 refrigerant fiuid fromsaid cyinder after the motor attains a certain speed. In practicing theinvention, a valve is used to close the by-passing and this valve isarranged so that iteffectively closes the by-pass by mechanicallyoperated means, which are assisted by the pressure created within thecompression cylinder after the motor attains a predetermined speed'.;-

Other objects and advantages wfll be apparent' from the followingdescription and accompanying drawings, wherein a preferred form of the.present invention is clearly shown.-

In the drawings: Fig. 1 is a view showing a refrigerating systemembodying features of my invention, partly illustrated diagrammaticallyand an enlarged ver- Another object of my invention is to provide ticalcross sectional showing of the motor-compressor unit; and

Fig. 2 is a view in cross section, taken along the line 22 of Fig. 1.

In many refrigerating machines heretofore constructed, a separatecompressor and a motor for driving the same have been provided with anexternal drive shaft for connecting the motor to the compressor. Suchmachines, however, require the provision of a stuffing. box for thecompressor shaft to prevent the escape of refrigerant fluid from, or theadmission of air into, the

compressor housing. These stufling boxes required considerable attentionto maintain a seal which was entirely fluid-tight. As refrigeratingmachines of the household type have a relatively small volumetriccapacity, a slight amount of leakage of refrigerant or infiltration ofair will interfere materially with the successful operation of themachine. In addition, it has been found that stufling boxes after theyhave been used over an appreciable length of time become noisy, whichrenders the apparatus entirely unsuitable for household use.Refrigerating machines of this character are generally referred to as ofthe open type.

It has also been proposed to have the compressor and its driving motorlocated in a single, hermetically sealed casing adapted to containrefrigerant fluid. With such an arrangement, the stuffing box isentirely unnecessary as the entire operating mechanism may be confinedwithin the interior of the casing, whereby complete fluidtightness ofthe refrigerating system is assured. Refrigerating machines of thischaracter are generally referred to as the enclosed type. Withrefrigerating machines of the open type, a fan is usually mounted on themotor or compressor shaft for cooling the condenser. However, withmachines of the enclosed type, the fan for cooling the condenser must belocated on the exterior of the casing and, to drive this far, it haspreviously been proposed to provide a separate small motor. Thisnecessitated the use of two motors together with starting and controlappamotors are provided and the fan motor fails to.

operate, inadequate condensation of the gaseous refrigerant will resultand dangerous high pressures will be produced'as longer, the compressorcontinues to operate.

in any way affecting the hermetical sealing of the enclosing casing. Bythis arrangement, stuiflng boxes are eliminated and only onemotor is.required.

Referring now to the drawings for a more detailed description of myinvention, the numeral 28 designates, in general, a refrigerating systemcomprising a motor-compressor unit 22, condenser 24, evaporator 26 and ahigh side float mechanism 21. The motor-compressor unit comprises afluid-tight or hermetically sealed casing 38, which includes a centralcylindrically shaped casing 32 and removable end casting portions orplates 33 and 35. Within the casing 38 there is disposed a motor 38 andcompressor 48. The motor and compressor are operatively connectedtogether by means of a drive shaft 42 which is journalled on one endthereof in a bearing 43 carried by end plate 33. The opposite end of theshaft 42 is provided with a reduced portion 45- which is journalled in abearing 41 carried by removable end plate 35. The motor 38 includes arotor 58, which is preferably press-fitted on the drive shaft 42, and astator 52 carried by casting 32. The compressor includes a cylinder body54, piston 55 which is adapted to be reciprocated in a cylinder 51 bymeans of connecting rod 58 operatively connected to the piston and aneccentric portion 68 of the drive shaft 42.

In order to provide means for cooling the condenser, a fan 64 has beenprovided. Preferably,

the fan 64 is operated by power received from motor 38, which drives thecompressor 48. In order to accomplish this, I have provided a mechanicalconnection between the motor 38 and the fan 64 and arranged suchconnection in such a manner that power is transmitted to the fanwithout, in any away, affecting the fluid-tight qualities of thehermetically sealed casing.

/ {The improved mechanical drive connection between the motor 38 and fan84 comprises, in general, wobble shaft means I8. The shaft means 18comprises, in general, a yoke-shaped member I2 which serves to connectshaft ends 14 and 15. Between the ends of the yoke-shaped member I8there is disposed a stationary pivot bearing support 11 for supportingthe shaft means. Also, between the ends of the yoke-shaped member I2there is provided a pivot point member III which is rigidly connected tothe shaft means I8. This pivot point I9 is adapted to engage one side ofthe supporting member I! and provides a point contact therebetween. Inorder to maintain engagement between the pivot point i8 and thesupporting member ",1 have provided a second pivot point 88, which isadapted .to engage, by

is carried by means of a laterally extending portion 88 formedintegrally with acover plate 82 which isclamped between an end ring 84and the removable end plate 35 by means of screws 35. The shaft end I4,pivot points I8 and 88 and the yoke-shaped member 12 are enclosed bymeans of a flexible expansible bellows 81 which is sealed upon one endthereof to flange 98 on the cover plate 82, and the opposite end issealed to a membe! I88 to which the end I5 of the shaft is screwthreaded and preferably soldered so as to provide a fluid-tight jointtherebetween.

From the foregoing, it will be apparent that the casing 32 and plates 33and 35, together with the cover plate 32 and expansible bellows 91,provide a fluid-tight or hermetically sealed casing which entirelyencloses the motor and compressor units.

In order to provide a suitable mounting for the fan 84, I have provideda casting I85, which is preferably carried by the end plate 35, to whichthe casting I 85.is secured by any suitable means. The casting alsoprovides a housing for the flexible bellows and wobble shaft means. Thefan 64 is carried by a suitable small shaft I8I which is journalled in abearing I88 which is preferably press-fltted within the casting I85.-The shaft is provided with an enlarged head portion H8 in which there isprovided a recess III for receiving aspherically shaped end H3 of thewobble shaft-means. Within the hollow portion 5 of the reduced portion48 of the drive shaft, there is disposed a socket member II8 providedwith a recess I28 for receiving a spherically shaped end 122 of thewobble shaft. As will be noted in Fig. l, the recesses Ill and I28 areeccentrically disposed with reference to the axis of the drive shaft andfan shaft. By this arrangement, movement of the drive shaft will affectorbital movements of the ends 3 and I22 of the shaft means to effectrotation of the fan 64. By the present arrangement, it will be notedthat the pivot point I3 is held in engagement with the support member 11by means of the pivot point 88 and spring 82. Consequently, any

movement of the wobble shaft will be substantially if not entirely, freefrom friction, since there is but a point contact between the shaftmeans and its support.

In order to provide for lubricating moving elements of the compressorand fan driving mechanism, I have provided a well I25 in the end plate33 for receiving 011 from the lower portion of the casing 32 by means ofan oil flinger I21 Oil received in the well flows through passage I28intoa radial bore I29 in the drive shaft. Oil passes through the boreinto-the hollow portion H5 of the reduced end of the shaft 45, whence itpasses to the: bearing support and pivot points. In the event a largeamount of oil is ac'eumulated within the expansible bellows, it mayreadily be returned to the interior of the casing through passage I3I.This prevents the accumulation of too large a quantity of oil within theinterior of the bellows, which would prevent proper movement of saidbellows.

The fan shaft I81 is provided with lubrication .by means of a wick I35formed of a body of fibrous material disposed within a cavity I36adjacent the shaft and bearing in casting I85. when the device isassembled, a quantity of oil may be disposed within the casting, whichis in open communication with the cavity through passage I38. Thus, theoil within the casting will supply lubricant to the wick, which in turnwill, by

capillary action, lubricate the shaft I01 and required for the shaft andbearing, it may be supplied readily by removing plate I40 and insertingthrough opening MI.

During operation of the apparatus hereinbefore described, the compressorwithdraws gaseous refrigerant from the evaporator through a vaporconduit I50, compresses the gaseous refrigerant-and delivers it to thecondenser wherein it is liquefied and from which it is delivered to thehigh side float mechanism. Liquid refrigerant is supplied to theevaporator by means of a liquid supply conduit I52. As shown in Fig. 2,gaseous refrigerant enters the compressor through an intake chamber I54,whence it passes into the cylinder under the control of a reed valveI55. The compressed refrigerant is discharged from the compressioncylinder through a discharge-valve mechanism I51, whence it passes intoan. outlet or discharge chamber I60 and through conduit I02 tocondenser. In the event any oil is returned from the evaporator to thecompressor, it will, upon entering the intake chamber, descend into thelower portion thereof and pass through an opening I69, which is incommunication with the interior of the casing 30.

As will be noted in the drawings, the intake and discharge chambers areconsiderably larger than the cross sectional interior area of the intakeconduit I50 and discharge conduitl62. By providing a suction chamber ofthis type, it has been found that it acts as an oil separator and whichprovides for automatically retm-ning oil to the crankcase. A relativelylarge suction chamber also acts as a gas surge chamber which I evens outthe periodic suction of the cylinder to an even flow of gas through thesuction line. By providing a relatively large discharge chamher, it hasbeen found that it acts as a surge chamber to even out the dischargefrom the cylinder, which is periodic, to even the flow through thedischarge conduit. The discharge chamber also acts as a silencer of thedischarged gas through the discharge valve.

Preferably, the motor-compressor unit is intermittently operated and inorder to control the operation of the motor-compressor unit, anysuitable thermostatically controlled switch may be provided which isresponsive to changes of temperatures in the compartment to be cooled byevaporator, or responsive to changes in temperature in evaporator. Ifdesired, a suitable low pressure control of the well known type may beprovided for controlling the operation of the motor-compressor unit inaccordance with iggnges of pressure within the vapor conduit Preferably,the motor is of the split phase type and has a low starting torque.Under these con- ;ditions, it has been found desirable to provide somesort of an unloader to allow the motor to come up to speed beforeassuming the load of the compressor. Thus, I- have provided an improvedunloader I00 which is adapted to hold a alve member I82 away from itsseat I03 until the speed of the motor attains a certain value. By thisarrangement, gas entering the compression chamber is by-passed throughpassage I85 into the interior of the casing and no work is accomplishedby the compressor until such certain speed is attained by the motorand'the valve member is closed by the unloader actuating mechanism. whenthe valve member is in the closed position any pressures created withinthe as to minimize frictionallosses.

compression cylinder tends to maintain or to urge the valve membertowards its seat. The unloader actuating mechanism comprises a suitablesliding collar I01 carried by the drive shaft, which is adapted to bemoved by means of a 5 finger disposed within a recess I80 of the collar1 I81. When the motor begins to operate the unloader actuating mechanismdoes not effect movement of the valve I02 until the speed of said motorattains a certainvalue. When such a speed is attained, a pair of weightsI90, which are actuated by centrifugal force against the action ofsprings I92, tend to move the finger I88 toward the left side view inthe drawings to move the collar in that direction. When this takesplace, a lever I94 is moved by the action of a spring I96 and thislever, by means of pushrod I91, tends to move the valve memberdownwardly to close the valve. When the compressor ceases operation, theslidable collar I81 is returned to the position shown in Fig. 1 of thedrawings by the action of springs I92, which overcome the action ofspring I90 to slide the collar I81 which moves lever I94 and push rodI01 to open valve I82.

From the foregoing, it will be noted that I have provided arefrigerating system of the type including a refrigerant compressor, amotor for driving the compressor, a condenser and a refrigerantevaporator and an improved arrangement for cooling the condenser, whichis especially applicable to refrigerating apparatus wherein the motorand the compressor are both entirely enclosed within the fluid-tight orhermetically sealed casing. Also, it will be noted'that I haveprovidedfor a fan located outside of the casing for cooling thecondenser by power received from the compressor driving motor without,in any way, effecting the fluid-tight qualitiesof the her; meticaliysealed casing. In addition, I have profvided for operating the fan insuch a manner so Although only a preferred form of the mven-F tion hasbeen illustrated, and that form described indetail, it will be apparentto those skilled in the, 46

art that various modifications maybe made therein without departing fromthe spirit of the invention or from the scope of the appended, claims.

I claim:

1. A power transmitting Joint comprising a wall, a wobbling shaftassociated with said wall and being adapted for transmitting power, abearing support for the shaft, and anti-friction means associated withthe shaft and said hearing support and being arranged for providing apoint contact between itself and said bearing support intermediate theends of said shaft.

2. A power transmitting joint comprising a flexible wall, a wobblingshaft associated with 00 said flexible wall and being arranged fortransmitting power, a bearing support for the shaft, and anti-frictionmeans associated with said bearing support and said shaft intermediatethe ends of said shaft, said anti-friction means being 65 arranged forproviding a pointed contacting engagement between itself and saidbearing support which is relatively small with respect to the size ofsaid shaft.

3. A power transmitting joint comprising a 70 wall, a wobbling shaftassociated with said wall and being adapted for transmitting-power, andpivoted means for supporting said shaft witha pointed relatively smallcontacting surface wi respect to the size of said shaft. 15

' 4. A power transmitting joint comprising a wall, a wobbling shaftextending through said wall for transmitting power, a bearing supportfor the shaft, anti-friction means providing a point contact betweensaid shaft and said bear-- 1 point associated with'the shaft and inengage- -ment with said pivot bearing member.

7. 'A device with which to connect a rotatable element within ahermetically sealed casing with a rotatable element located outside of-the casing comprising a wobble shaft extending through a wall of saidcasing, a support for the shaft intermediate its ends, and a pivot pointoperatively associated with said shaft and said support, the ends ofsaid shaft being eccentrically connected to said rotatable elementswhereby movement of one of said rotatable elements will eifect orbitalmovements of the ends of the wobble shaft to transmit rotary motion fromone ofsaid rotatable elements to the other.

8. 'A device with which to connect a rotatable element within ahermetically sealed casing with a rotatable element located outside ofthe casing comprising a wobble shaft extending through a wall of saidcasing, a support for the shaft intermediate its ends, means connectingthe shaft to said support and resilient means including a bellows and aspring urging said first means toward said support.

' 9. A device with which to connect a rotatable element within ahermetically sealed casing with a rotatable element iocatedoutside ofthe casing comprising a wobble shaft extending through a wall of saidcasing, a support for the shaft intermediate its ends. an expansiblebellows responsive to pressures within the casing forsealing the jointbetween the shaft and the casing. means connecting the shaft to saidsupport and means including a spring which cooperates with I the actionof said bellows for urging said first named means toward said support.

' 10. 'A device with which to-coiinect a rotatable element within ahermetically sealed casing with a rotatable element located outside ofthe casing comprising a wobble shaft extending through a wall of saidcasing, said shaft including a yoke- 5 shaped member between the endsthereof, a stationary support for the shaft disposed between the ends ofthe yoke-shaped member, and a pivot point carried by the shaft inengagement with said support. 1o

11. A device with which to connect a rotatable element within ahermetically sealed casing with arotatable element located outside ofthe casing comprising a wobble shaftextending through a -wall of saidcasing. said shaft includ- 1-'5 ing a yoke-shaped member between theends thereof, a stationary'support for the shaft disposed between theends of the yoke-shaped memher, a pivot point carried by the shaft inengagement with one side of said support and a thereof. a stationarysupport for the shaft disposed between the ends of the yoke-shapedmember, a pivot point'carried by the shaft in engagement with one sideof said support. a second pivot point associated with said shaft and inengagement with the opposite side of said support, and a springassociated with the second pivot point for maintaining engagementbetween the first named pivot point and said support.

13. A device with which to connect a rotatable element within ahermetically sealed casing with 4 a rotatable element located outside ofthe casing comprising a wobble shaft extending through a wall of saidcasing, said shaft including a yoke-shaped member between the endsthereof and a stationary member disposed between the ends of theyoke-shaped member for mp rti s 14. A device with which to connect onerotat able element with another comprising a wobble shaft including ayoke-shaped member intermediate its ends and a stationary member'disposed between the ends of said yoke-shaped member for supportingsaid shaft.

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